The invention relates generally to the field of object security authentication, and more particularly to the use of encoded images for authentication of documents and other objects.
Document falsification and product counterfeiting are significant problems that have been addressed in a variety of ways. One of the more successful approaches has been the use of latent or hidden images applied to or printed on objects to be protected. These images are generally not viewable without the assistance of specialized devices that render them visible.
One approach to the formation of a latent image is to optically encode the image so that, when printed, the image can be viewed only through the use of a corresponding decoding device. Such graphical encoded images may be used on virtually any form of printed document including legal documents, identification cards and papers, labels, currency, stamps, etc. They may also be applied to goods or packaging for goods subject to counterfeiting.
Objects to which a graphical encoded image is applied may be authenticated by decoding the encoded image and comparing the decoded image to an expected authentication image. The authentication image may include information specific to the object being authenticated or information relating to a group of similar objects (e.g., products produced by a particular manufacturer or facility). Production and application of encoded images may be controlled so that they cannot easily be duplicated. Further, the encoded image may be configured so that tampering with the information on the document or label is readily apparent.
The effectiveness of using graphical encoded images to prevent counterfeiting or unauthorized production of documents and other products may depend on the security of the software and the encoding parameters used to encode an authentication image. It can also depend on controlling access to the system that applies the final encoded image to the objects to be authenticated. Unauthorized knowledge of the encoding parameters or the authentication image used to produce an encoded image may make it possible to duplicate the encoded image and apply it to non-authentic goods or documents.
As a consequence, measures must be taken to assure the security of the encoding process and to make the process difficult or impossible to reverse engineer or duplicate.